<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button>test1</button>
    <button>test2</button>
    <button id="btn3">test3</button>
    <button>test4</button>
    <script src="js/jquery-3.5.1.min.js"></script>
    <script>
        var $buttons = $('button')
        console.log($buttons.length)
        console.log($buttons[1].innerHTML,$buttons.get(1).innerHTML)
        console.log($('#btn3').index()) 

    </script>
</body>
</html>